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Improve stack overflow recovery

Browse source 
It's now possible to use sigaltstack() to recover from stack overflows
on Windows. Several bugs in sigaltstack() have been fixed, for all our
supported platforms. There's a newer better example showing how to use
this, along with three independent unit tests just to further showcase
the various techniques.
This commit is contained in:
Justine Tunney 2023-10-04 07:07:43 -07:00
parent 1694edf85c
commit 4631d34d0d
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
24 changed files with 590 additions and 274 deletions
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142
examples/stackoverflow.c
View file

@ -7,74 +7,104 @@
│ • http://creativecommons.org/publicdomain/zero/1.0/ │
╚─────────────────────────────────────────────────────────────────*/
#endif
#include "libc/calls/calls.h"
#include "libc/dce.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/sigaltstack.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/calls/struct/ucontext.internal.h"
#include "libc/calls/ucontext.h"
#include "libc/intrin/kprintf.h"
#include "libc/limits.h"
#include "libc/log/check.h"
#include "libc/mem/gc.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/stack.h"
#include "libc/stdio/stdio.h"
#include "libc/sysv/consts/prot.h"
#include "libc/runtime/sysconf.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/ss.h"
#include "libc/testlib/testlib.h"
#include "libc/thread/thread.h"
/**
* @fileoverview Stack Overflow Demo
* stack overflow recovery technique #3
* rewrite thread cpu state to call pthread_exit
* this method returns gracefully from signal handlers
* unfortunately it relies on cpu architecture knowledge
*
* @see test/libc/thread/stackoverflow1_test.c
* @see test/libc/thread/stackoverflow2_test.c
* @see test/libc/thread/stackoverflow3_test.c
*/
#define N INT_MAX
volatile bool smashed_stack;
int A(int f(), int n) {
if (n < N) {
void Exiter(void *rc) {
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(0, ss.ss_flags);
pthread_exit(rc);
}
void CrashHandler(int sig, siginfo_t *si, void *arg) {
ucontext_t *ctx = arg;
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
smashed_stack = true;
ASSERT_TRUE(__is_stack_overflow(si, ctx));
//
// the backtrace will look like this
//
// 0x000000000042561d: pthread_exit at pthread_exit.c:99
// 0x0000000000418777: Exiter at stackoverflow2_test.c:40
// 0x00000000004186d8: CrashHandler at stackoverflow2_test.c:49
// 0x000000000041872a: StackOverflow at stackoverflow2_test.c:53
// 0x000000000041872a: StackOverflow at stackoverflow2_test.c:53
// 0x000000000041872a: StackOverflow at stackoverflow2_test.c:53
// ...
//
ctx->uc_mcontext.ARG0 = 123;
ctx->uc_mcontext.PC = (long)Exiter;
ctx->uc_mcontext.SP += 32768;
ctx->uc_mcontext.SP &= -16;
ctx->uc_mcontext.SP -= 8;
}
int StackOverflow(int f(), int n) {
if (n < INT_MAX) {
return f(f, n + 1) - 1;
} else {
return N;
return INT_MAX;
}
}
int (*Ap)(int (*)(), int) = A;
int (*pStackOverflow)(int (*)(), int) = StackOverflow;
void *MyPosixThread(void *arg) {
struct sigaction sa;
struct sigaltstack ss;
ss.ss_flags = 0;
ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 4096;
ss.ss_sp = gc(malloc(ss.ss_size));
ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
sa.sa_flags = SA_SIGINFO | SA_ONSTACK; // <-- important
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = CrashHandler;
sigaction(SIGBUS, &sa, 0);
sigaction(SIGSEGV, &sa, 0);
exit(pStackOverflow(pStackOverflow, 0));
return 0;
}
int main(int argc, char *argv[]) {
if (IsWindows()) {
fprintf(stderr, "stack overflow not possible to catch on windows yet\n");
exit(1);
}
ShowCrashReports();
return !!Ap(Ap, 0);
void *res;
pthread_t th;
struct sigaltstack ss;
smashed_stack = false;
pthread_create(&th, 0, MyPosixThread, 0);
pthread_join(th, &res);
ASSERT_EQ((void *)123L, res);
ASSERT_TRUE(smashed_stack);
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(SS_DISABLE, ss.ss_flags);
}
/*
error: Uncaught SIGSEGV (Stack Overflow) on rhel5 pid 368
./o//examples/stackoverflow.com
EUNKNOWN[No error information][0]
Linux rhel5 2.6.18-8.el5 #1 SMP Thu Mar 15 19:46:53 EDT 2007
0x0000000000406896: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
0x0000000000406898: A at examples/stackoverflow.c:24
etc. etc.
RAX 0000000000000000 RBX 0000000000000001 RDI 000000000040687e ST(0) 0.0
RCX 0000000000417125 RDX 000000000041cd70 RSI 0000000000000efe ST(1) 0.0
RBP 00006ffffffe1000 RSP 00006ffffffe1000 RIP 0000000000406897 ST(2) 0.0
R8 0000000000000000 R9 0000000000000022 R10 0000000000000008 ST(3) 0.0
R11 0000000000000293 R12 0000000000000001 R13 00007ffc70b4fc48 ST(4) 0.0
R14 00007ffc70b4fc58 R15 00007ffc70b4fd18 VF IF
XMM0 00000000000000000000000000000000 XMM8 00000000000000000000000000000000
XMM1 ffffffffffffeb030000000000000000 XMM9 00000000000000000000000000000000
XMM2 0000000000000000ffffffffffffffff XMM10 00000000000000000000000000000000
XMM3 00000000000000000000000000000000 XMM11 00000000000000000000000000000000
XMM4 00000000000000000000000000000000 XMM12 00000000000000000000000000000000
XMM5 00000000000000000000000000000000 XMM13 00000000000000000000000000000000
XMM6 00000000000000000000000000000000 XMM14 00000000000000000000000000000000
XMM7 00000000000000000000000000000000 XMM15 00000000000000000000000000000000
100080000000-100080030000 rw-pa-- 3x automap
6ffffffe0000-6fffffff0000 rw-paSF 1x stack
# 4 frames mapped w/ 0 frames gapped
*/

5
libc/calls/parsepromises.c
View file

@ -35,7 +35,8 @@ static int FindPromise(const char *name) {
*
* @return 0 on success, or -1 if invalid
*/
int ParsePromises(const char *promises, unsigned long *out) {
int ParsePromises(const char *promises, unsigned long *out,
unsigned long current) {
int rc = 0;
int promise;
unsigned long ipromises;
@ -57,7 +58,7 @@ int ParsePromises(const char *promises, unsigned long *out) {
rc = -1;
}
} else {
ipromises = 0;
ipromises = current;
}
if (!rc) {
*out = ipromises;

7
libc/calls/pledge.c
View file

@ -239,9 +239,6 @@
int pledge(const char *promises, const char *execpromises) {
int e, rc;
unsigned long ipromises, iexecpromises;
if (promises && !execpromises) {
execpromises = promises;
}
if (!promises) {
// OpenBSD says NULL argument means it doesn't change, i.e.
// pledge(0,0) on OpenBSD does nothing. The Cosmopolitan Libc
@ -262,8 +259,8 @@ int pledge(const char *promises, const char *execpromises) {
return -1;
} else if (!IsTiny() && IsGenuineBlink()) {
rc = 0; // blink doesn't support seccomp; avoid noisy log warnings
} else if (!ParsePromises(promises, &ipromises) &&
!ParsePromises(execpromises, &iexecpromises)) {
} else if (!ParsePromises(promises, &ipromises, __promises) &&
!ParsePromises(execpromises, &iexecpromises, __execpromises)) {
if (IsLinux()) {
// copy exec and execnative from promises to execpromises
iexecpromises = ~(~iexecpromises | (~ipromises & (1ul << PROMISE_EXEC)));

2
libc/calls/pledge.internal.h
View file

@ -14,7 +14,7 @@ struct Pledges {
extern const struct Pledges kPledge[PROMISE_LEN_];
int sys_pledge_linux(unsigned long, int);
int ParsePromises(const char *, unsigned long *);
int ParsePromises(const char *, unsigned long *, unsigned long);
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

133
libc/calls/sig.c
View file

@ -34,6 +34,7 @@
#include "libc/fmt/itoa.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/describebacktrace.internal.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/popcnt.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
@ -72,9 +73,6 @@ struct ContextFrame {
struct NtContext nc;
};
void __stack_call(int, siginfo_t *, void *, long,
void (*)(int, siginfo_t *, void *), void *);
static textwindows bool __sig_ignored_by_default(int sig) {
return sig == SIGURG || //
sig == SIGCONT || //
@ -90,9 +88,21 @@ textwindows bool __sig_ignored(int sig) {
static textwindows bool __sig_should_use_altstack(unsigned flags,
struct CosmoTib *tib) {
return (flags & SA_ONSTACK) && //
tib->tib_sigstack_size && //
!(tib->tib_sigstack_flags & (SS_DISABLE | SS_ONSTACK));
if (!(flags & SA_ONSTACK)) {
return false; // signal handler didn't enable it
}
if (!tib->tib_sigstack_size) {
return false; // sigaltstack() wasn't installed on this thread
}
if (tib->tib_sigstack_flags & SS_DISABLE) {
return false; // sigaltstack() on this thread was disabled by user
}
char *bp = __builtin_frame_address(0);
if (tib->tib_sigstack_addr <= bp &&
bp <= tib->tib_sigstack_addr + tib->tib_sigstack_size) {
return false; // we're already on the alternate stack
}
return true;
}
static textwindows wontreturn void __sig_terminate(int sig) {
@ -129,20 +139,6 @@ static textwindows sigaction_f __sig_handler(unsigned rva) {
return (sigaction_f)(__executable_start + rva);
}
static textwindows void __sig_call(int sig, siginfo_t *si, ucontext_t *ctx,
unsigned rva, unsigned flags,
struct CosmoTib *tib) {
++__sig.count;
if (__sig_should_use_altstack(flags, tib)) {
tib->tib_sigstack_flags |= SS_ONSTACK;
__stack_call(sig, si, ctx, 0, __sig_handler(rva),
tib->tib_sigstack_addr + tib->tib_sigstack_size);
tib->tib_sigstack_flags &= ~SS_ONSTACK;
} else {
__sig_handler(rva)(sig, si, ctx);
}
}
textwindows int __sig_raise(int sig, int sic) {
unsigned rva, flags;
struct CosmoTib *tib = __get_tls();
@ -160,7 +156,7 @@ textwindows int __sig_raise(int sig, int sic) {
STRACE("entering raise(%G) signal handler %t with mask %s → %s", sig,
__sig_handler(rva), DescribeSigset(0, &ctx.uc_sigmask),
DescribeSigset(0, &(sigset_t){{pt->tib->tib_sigmask}}));
__sig_call(sig, &si, &ctx, rva, flags, tib);
__sig_handler(rva)(sig, &si, &ctx);
STRACE("leaving raise(%G) signal handler %t with mask %s → %s", sig,
__sig_handler(rva),
DescribeSigset(0, &(sigset_t){{pt->tib->tib_sigmask}}),
@ -258,9 +254,7 @@ static textwindows int __sig_killer(struct PosixThread *pt, int sig, int sic) {
}
uintptr_t sp;
if (__sig_should_use_altstack(flags, pt->tib)) {
pt->tib->tib_sigstack_flags |= SS_ONSTACK;
sp = (uintptr_t)pt->tib->tib_sigstack_addr + pt->tib->tib_sigstack_size;
pt->tib->tib_sigstack_flags &= ~SS_ONSTACK;
} else {
sp = (nc.Rsp - 128 - sizeof(struct ContextFrame)) & -16;
}
@ -338,11 +332,11 @@ static int __sig_crash_sig(struct NtExceptionPointers *ep, int *code) {
case kNtSignalPrivInstruction:
*code = ILL_PRVOPC;
return SIGILL;
case kNtSignalGuardPage:
case kNtSignalInPageError:
case kNtStatusStackOverflow:
*code = SEGV_MAPERR;
return SIGSEGV;
case kNtSignalGuardPage:
case kNtSignalAccessViolation:
*code = SEGV_ACCERR;
return SIGSEGV;
@ -386,26 +380,25 @@ static int __sig_crash_sig(struct NtExceptionPointers *ep, int *code) {
}
}
// abashed the devil stood, and felt how awful goodness is
__msabi unsigned __sig_crash(struct NtExceptionPointers *ep) {
int code, sig = __sig_crash_sig(ep, &code);
static void __sig_crasher(struct NtExceptionPointers *ep, int code, int sig,
struct CosmoTib *tib) {
// increment the signal count for getrusage()
++__sig.count;
// log vital crash information reliably for --strace before doing much
// we don't print this without the flag since raw numbers scare people
// this needs at least one page of stack memory in order to get logged
// otherwise it'll print a warning message about the lack of stack mem
STRACE("win32 vectored exception 0x%08Xu raising %G "
"cosmoaddr2line %s %lx %s",
ep->ExceptionRecord->ExceptionCode, sig, program_invocation_name,
ep->ContextRecord->Rip,
DescribeBacktrace((struct StackFrame *)ep->ContextRecord->Rbp));
if (sig == SIGTRAP) {
ep->ContextRecord->Rip++;
if (__sig_ignored(sig)) {
return kNtExceptionContinueExecution;
}
}
struct PosixThread *pt = _pthread_self();
siginfo_t si = {.si_signo = sig,
.si_code = code,
.si_addr = ep->ExceptionRecord->ExceptionAddress};
// if the user didn't install a signal handler for this unmaskable
// exception, then print a friendly helpful hint message to stderr
unsigned rva = __sighandrvas[sig];
unsigned flags = __sighandflags[sig];
if (rva == (intptr_t)SIG_DFL || rva == (intptr_t)SIG_IGN) {
#ifndef TINY
intptr_t hStderr;
@ -418,16 +411,74 @@ __msabi unsigned __sig_crash(struct NtExceptionPointers *ep) {
#endif
__sig_terminate(sig);
}
// if this signal handler is configured to auto-reset to the default
// then that reset needs to happen before the user handler is called
unsigned flags = __sighandflags[sig];
if (flags & SA_RESETHAND) {
STRACE("resetting %G handler", sig);
__sighandrvas[sig] = (int32_t)(intptr_t)SIG_DFL;
}
// determine the true memory address at which fault occurred
// if this is a stack overflow then reapply guard protection
void *si_addr;
if (ep->ExceptionRecord->ExceptionCode == kNtSignalGuardPage) {
si_addr = (void *)ep->ExceptionRecord->ExceptionInformation[1];
} else {
si_addr = ep->ExceptionRecord->ExceptionAddress;
}
// call the user signal handler
// with a temporarily replaced signal mask
// and a modifiable view of the faulting code's cpu state
// note ucontext_t is a hefty data structures on top of NtContext
ucontext_t ctx = {0};
siginfo_t si = {.si_signo = sig, .si_code = code, .si_addr = si_addr};
_ntcontext2linux(&ctx, ep->ContextRecord);
ctx.uc_sigmask.__bits[0] = pt->tib->tib_sigmask;
__sig_call(sig, &si, &ctx, rva, flags, pt->tib);
pt->tib->tib_sigmask = ctx.uc_sigmask.__bits[0];
ctx.uc_sigmask.__bits[0] = tib->tib_sigmask;
__sig_handler(rva)(sig, &si, &ctx);
tib->tib_sigmask = ctx.uc_sigmask.__bits[0];
_ntlinux2context(ep->ContextRecord, &ctx);
}
void __stack_call(struct NtExceptionPointers *, int, int, struct CosmoTib *,
void (*)(struct NtExceptionPointers *, int, int,
struct CosmoTib *),
void *);
//
// abashed the devil stood
// and felt how awful goodness is
//
__msabi dontinstrument unsigned __sig_crash(struct NtExceptionPointers *ep) {
// translate win32 to unix si_signo and si_code
int code, sig = __sig_crash_sig(ep, &code);
// advance the instruction pointer to skip over debugger breakpoints
// this behavior is consistent with how unix kernels are implemented
if (sig == SIGTRAP) {
ep->ContextRecord->Rip++;
if (__sig_ignored(sig)) {
return kNtExceptionContinueExecution;
}
}
// win32 stack overflow detection executes INSIDE the guard page
// thus switch to the alternate signal stack as soon as possible
struct CosmoTib *tib = __get_tls();
unsigned flags = __sighandflags[sig];
if (__sig_should_use_altstack(flags, tib)) {
__stack_call(ep, code, sig, tib, __sig_crasher,
tib->tib_sigstack_addr + tib->tib_sigstack_size);
} else {
__sig_crasher(ep, code, sig, tib);
}
// resume running user program
// hopefully the user fixed the cpu state
// otherwise the crash will keep happening
return kNtExceptionContinueExecution;
}

63
libc/calls/sigaltstack.c
View file

@ -57,51 +57,36 @@ static void sigaltstack2linux(struct sigaltstack *linux,
static textwindows int sigaltstack_cosmo(const struct sigaltstack *neu,
struct sigaltstack *old) {
struct CosmoTib *tib;
tib = __get_tls();
struct CosmoTib *tib = __get_tls();
char *bp = __builtin_frame_address(0);
if (old) {
old->ss_sp = tib->tib_sigstack_addr;
old->ss_size = tib->tib_sigstack_size;
old->ss_flags = tib->tib_sigstack_flags;
old->ss_flags = tib->tib_sigstack_flags & ~SS_ONSTACK;
}
if (neu) {
tib->tib_sigstack_addr = (char *)ROUNDUP((uintptr_t)neu->ss_sp, 16);
tib->tib_sigstack_size = ROUNDDOWN(neu->ss_size, 16);
tib->tib_sigstack_flags &= SS_ONSTACK;
tib->tib_sigstack_flags |= neu->ss_flags & SS_DISABLE;
tib->tib_sigstack_flags = neu->ss_flags & SS_DISABLE;
}
if (tib->tib_sigstack_addr <= bp &&
bp <= tib->tib_sigstack_addr + tib->tib_sigstack_size) {
if (old) old->ss_flags |= SS_ONSTACK;
tib->tib_sigstack_flags = SS_ONSTACK; // can't disable if on it
} else if (!tib->tib_sigstack_size) {
if (old) old->ss_flags = SS_DISABLE;
tib->tib_sigstack_flags = SS_DISABLE;
}
return 0;
}
static int sigaltstack_sysv(const struct sigaltstack *neu,
struct sigaltstack *old) {
void *b;
const void *a;
struct sigaltstack_bsd bsd;
if (IsLinux()) {
a = neu;
b = old;
} else {
if (neu) {
sigaltstack2bsd(&bsd, neu);
a = &bsd;
} else {
a = 0;
}
if (old) {
b = &bsd;
} else {
b = 0;
}
}
if (!sys_sigaltstack(a, b)) {
if (IsBsd() && old) {
sigaltstack2linux(old, &bsd);
}
return 0;
} else {
return -1;
}
static int sigaltstack_bsd(const struct sigaltstack *neu,
struct sigaltstack *old) {
struct sigaltstack_bsd oldbsd, neubsd, *neup = 0;
if (neu) sigaltstack2bsd(&neubsd, neu), neup = &neubsd;
if (sys_sigaltstack(neup, &oldbsd) == -1) return -1;
if (old) sigaltstack2linux(old, &oldbsd);
return 0;
}
/**
@ -131,13 +116,13 @@ int sigaltstack(const struct sigaltstack *neu, struct sigaltstack *old) {
rc = efault();
} else if (neu && ((neu->ss_size >> 32) || //
(neu->ss_flags & ~(SS_ONSTACK | SS_DISABLE)))) {
return einval();
rc = einval();
} else if (neu && neu->ss_size < __get_minsigstksz()) {
rc = enomem();
} else if (IsLinux() || IsBsd()) {
if (!(rc = sigaltstack_sysv(neu, old))) {
sigaltstack_cosmo(neu, old);
}
} else if (IsLinux()) {
rc = sys_sigaltstack(neu, old);
} else if (IsBsd()) {
rc = sigaltstack_bsd(neu, old);
} else {
rc = sigaltstack_cosmo(neu, old);
}

15
libc/intrin/describebacktrace.c
View file

@ -24,20 +24,19 @@
dontinstrument const char *(DescribeBacktrace)(char buf[N],
struct StackFrame *fr) {
bool gotsome = false;
char *p = buf;
char *pe = p + N;
bool gotsome = false;
while (fr) {
if (gotsome) {
if (p + 1 < pe) {
if (p + 16 + 1 + 1 <= pe) {
if (gotsome) {
*p++ = ' ';
*p = 0;
} else {
gotsome = true;
}
} else {
gotsome = true;
}
if (p + 17 <= pe) {
p = __hexcpy(p, fr->addr);
} else {
break;
}
fr = fr->next;
}

2
libc/intrin/getmainstack.c
View file

@ -103,7 +103,7 @@ void __get_main_stack(void **out_addr, size_t *out_size, int *out_guardsize) {
if (IsWindows()) {
*out_addr = (void *)GetStaticStackAddr(0);
*out_size = GetStaticStackSize();
*out_guardsize = 4096;
*out_guardsize = GetGuardSize();
return;
}
int pagesz = getauxval(AT_PAGESZ);

2
libc/intrin/strace.internal.h
View file

@ -3,7 +3,7 @@
#include "libc/intrin/likely.h"
#include "libc/runtime/runtime.h"
#define _NTTRACE 1 /* not configurable w/ flag yet */
#define _NTTRACE 0 /* not configurable w/ flag yet */
#define _POLLTRACE 0 /* not configurable w/ flag yet */
#define _DATATRACE 1 /* not configurable w/ flag yet */
#define _LOCKTRACE 0 /* not configurable w/ flag yet */

21
libc/intrin/wantcrashreports.c
View file

@ -1,21 +0,0 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/log/internal.h"
bool _wantcrashreports;

1
libc/log/internal.h
View file

@ -5,7 +5,6 @@
COSMOPOLITAN_C_START_
extern bool __nocolor;
extern bool _wantcrashreports;
extern bool g_isrunningundermake;
void __start_fatal(const char *, int);

1
libc/log/showcrashreports.c
View file

@ -91,7 +91,6 @@ void ShowCrashReports(void) {
InstallCrashHandler(SIGBUS, SA_RESETHAND);
InstallCrashHandler(SIGABRT, SA_RESETHAND);
InstallCrashHandler(SIGSEGV, SA_RESETHAND | SA_ONSTACK);
_wantcrashreports = true;
}
IGNORE_LEAKS(ShowCrashReports)

4
libc/nt/struct/ntexceptionrecord.h
View file

@ -2,7 +2,7 @@
#define COSMOPOLITAN_LIBC_NT_STRUCT_NTEXCEPTIONRECORD_H_
#define kNtExceptionMaximumParameters 15
#define kNtExceptionNoncontinuable 1
#define kNtExceptionNoncontinuable 1
#if !(__ASSEMBLER__ + __LINKER__ + 0)
@ -12,7 +12,7 @@ struct NtExceptionRecord {
struct NtExceptionRecord *ExceptionRecord; /* nested exceptions */
void *ExceptionAddress; /* %rip */
uint32_t NumberParameters; /* #ExceptionInformation */
uint32_t *ExceptionInformation[kNtExceptionMaximumParameters];
uint64_t ExceptionInformation[kNtExceptionMaximumParameters];
};
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

42
libc/runtime/isstackoverflow.c
View file

@ -19,45 +19,19 @@
#include "libc/calls/struct/siginfo.h"
#include "libc/calls/struct/ucontext.internal.h"
#include "libc/calls/ucontext.h"
#include "libc/intrin/kprintf.h"
#include "libc/macros.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/sig.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/thread.h"
#include "libc/thread/tls.h"
/**
* Returns true if signal is likely a stack overflow.
* Returns true if signal is most likely a stack overflow.
*/
char __is_stack_overflow(siginfo_t *si, void *ucontext) {
// check if signal has the information we need
ucontext_t *uc = ucontext;
if (!si) return false;
if (!uc) return false;
char __is_stack_overflow(siginfo_t *si, void *arg) {
ucontext_t *uc = arg;
if (!si || !uc) return false;
if (si->si_signo != SIGSEGV && si->si_signo != SIGBUS) return false;
// with threads we know exactly where the guard page is
int pagesz = getauxval(AT_PAGESZ);
uintptr_t addr = (uintptr_t)si->si_addr;
struct PosixThread *pt = _pthread_self();
if (pt->attr.__stacksize) {
uintptr_t stack = (uintptr_t)pt->attr.__stackaddr;
uintptr_t guard = pt->attr.__guardsize;
uintptr_t bot, top;
if (guard) {
bot = stack;
top = bot + guard;
} else {
bot = stack - pagesz;
top = stack;
}
return addr >= bot && addr < top;
}
// it's easy to guess with the main stack
// even though it's hard to know its exact boundaries
uintptr_t sp = uc->uc_mcontext.SP;
return addr <= sp && addr >= sp - pagesz;
intptr_t sp = uc->uc_mcontext.SP;
intptr_t fp = (intptr_t)si->si_addr;
return ABS(fp - sp) < getauxval(AT_PAGESZ);
}

16
libc/runtime/mmap.c
View file

@ -28,6 +28,7 @@
#include "libc/intrin/bsr.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/directmap.internal.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/likely.h"
#include "libc/intrin/safemacros.internal.h"
#include "libc/intrin/strace.internal.h"
@ -37,6 +38,9 @@
#include "libc/log/libfatal.internal.h"
#include "libc/log/log.h"
#include "libc/macros.internal.h"
#include "libc/nt/enum/memflags.h"
#include "libc/nt/enum/pageflags.h"
#include "libc/nt/memory.h"
#include "libc/nt/process.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/processmemorycounters.h"
@ -396,9 +400,15 @@ inline void *__mmap_unlocked(void *addr, size_t size, int prot, int flags,
kAsanMmapSizeOverrun);
}
if (needguard) {
unassert(!mprotect(p, pagesize, PROT_NONE));
if (IsAsan()) {
__asan_poison(p, pagesize, kAsanStackOverflow);
if (!IsWindows()) {
unassert(!mprotect(p, pagesize, PROT_NONE));
if (IsAsan()) {
__asan_poison(p, pagesize, kAsanStackOverflow);
}
} else {
uint32_t oldattr;
unassert(VirtualProtect(p, pagesize, kNtPageReadwrite | kNtPageGuard,
&oldattr));
}
}
}

3
libc/runtime/winmain.greg.c
View file

@ -169,6 +169,9 @@ static abi wontreturn void WinInit(const char16_t *cmdline) {
uint32_t old;
__imp_VirtualProtect((void *)stackaddr, stacksize, kNtPageReadwrite, &old);
}
uint32_t oldattr;
__imp_VirtualProtect((void *)stackaddr, GetGuardSize(),
kNtPageReadwrite | kNtPageGuard, &oldattr);
_mmi.p[0].x = stackaddr >> 16;
_mmi.p[0].y = (stackaddr >> 16) + ((stacksize - 1) >> 16);
_mmi.p[0].prot = prot;

22
libc/thread/pthread_create.c
View file

@ -31,6 +31,7 @@
#include "libc/intrin/bsr.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/dll.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/log/internal.h"
@ -38,6 +39,9 @@
#include "libc/mem/alloca.h"
#include "libc/mem/mem.h"
#include "libc/nexgen32e/crc32.h"
#include "libc/nt/enum/memflags.h"
#include "libc/nt/enum/pageflags.h"
#include "libc/nt/memory.h"
#include "libc/nt/runtime.h"
#include "libc/nt/synchronization.h"
#include "libc/runtime/runtime.h"
@ -210,9 +214,19 @@ static errno_t pthread_create_impl(pthread_t *thread,
-1, 0, 0) != pt->attr.__stackaddr) {
notpossible;
}
if (pt->attr.__guardsize && !IsWindows() &&
mprotect(pt->attr.__stackaddr, pt->attr.__guardsize, PROT_NONE)) {
notpossible;
if (pt->attr.__guardsize) {
if (!IsWindows()) {
if (mprotect(pt->attr.__stackaddr, pt->attr.__guardsize,
PROT_NONE)) {
notpossible;
}
} else {
uint32_t oldattr;
if (!VirtualProtect(pt->attr.__stackaddr, pt->attr.__guardsize,
kNtPageReadwrite | kNtPageGuard, &oldattr)) {
notpossible;
}
}
}
}
}
@ -227,7 +241,7 @@ static errno_t pthread_create_impl(pthread_t *thread,
}
}
pt->pt_flags |= PT_OWNSTACK;
if (IsAsan() && pt->attr.__guardsize) {
if (IsAsan() && !IsWindows() && pt->attr.__guardsize) {
__asan_poison(pt->attr.__stackaddr, pt->attr.__guardsize,
kAsanStackOverflow);
}

2
test/libc/calls/pledge_test.c
View file

@ -552,6 +552,8 @@ TEST(pledge_openbsd, execpromisesIsNull_letsItDoAnything) {
}
EXPECT_NE(-1, wait(&ws));
EXPECT_TRUE(WIFEXITED(ws));
EXPECT_FALSE(WIFSIGNALED(ws));
EXPECT_EQ(0, WTERMSIG(ws));
EXPECT_EQ(3, WEXITSTATUS(ws));
}

52
test/libc/thread/pthread_create_test.c
View file

@ -255,58 +255,6 @@ TEST(pthread_cleanup, pthread_normal) {
ASSERT_TRUE(g_cleanup2);
}
////////////////////////////////////////////////////////////////////////////////
jmp_buf recover;
volatile bool smashed_stack;
void CrashHandler(int sig, siginfo_t *si, void *ctx) {
kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
smashed_stack = true;
ASSERT_TRUE(__is_stack_overflow(si, ctx));
longjmp(recover, 123);
}
int StackOverflow(int f(), int n) {
if (n < INT_MAX) {
return f(f, n + 1) - 1;
} else {
return INT_MAX;
}
}
int (*pStackOverflow)(int (*)(), int) = StackOverflow;
void *MyPosixThread(void *arg) {
int jumpcode;
struct sigaction sa, o1, o2;
struct sigaltstack ss;
ss.ss_flags = 0;
ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 4096;
ss.ss_sp = gc(malloc(ss.ss_size));
ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
sa.sa_flags = SA_SIGINFO | SA_ONSTACK; // <-- important
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = CrashHandler;
sigaction(SIGBUS, &sa, &o1);
sigaction(SIGSEGV, &sa, &o2);
if (!(jumpcode = setjmp(recover))) {
exit(pStackOverflow(pStackOverflow, 0));
}
ASSERT_EQ(123, jumpcode);
sigaction(SIGSEGV, &o2, 0);
sigaction(SIGBUS, &o1, 0);
return 0;
}
TEST(cosmo, altstack_thread) {
pthread_t th;
if (IsWindows()) return;
pthread_create(&th, 0, MyPosixThread, 0);
pthread_join(th, 0);
ASSERT_TRUE(smashed_stack);
}
////////////////////////////////////////////////////////////////////////////////
// BENCHMARKS

104
test/libc/thread/stackoverflow1_test.c Normal file
View file

@ -0,0 +1,104 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/rlimit.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/sigaltstack.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/dce.h"
#include "libc/intrin/kprintf.h"
#include "libc/limits.h"
#include "libc/mem/gc.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/sysconf.h"
#include "libc/sysv/consts/rlimit.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/ss.h"
#include "libc/testlib/testlib.h"
#include "libc/thread/thread.h"
/**
* stack overflow recovery technique #1
* overflow the gigantic main process stack
* simple but it can upset kernels / libraries
*/
jmp_buf recover;
volatile bool smashed_stack;
void CrashHandler(int sig, siginfo_t *si, void *ctx) {
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
smashed_stack = true;
ASSERT_TRUE(__is_stack_overflow(si, ctx));
longjmp(recover, 123);
}
void SetUp(void) {
// tune down the main process's stack size to a reasonable amount
// some operating systems, e.g. freebsd, will do things like have
// 500mb RLIMIT_STACK by default, even on machines with 400mb RAM
struct rlimit rl = {2 * 1024 * 1024, 2 * 1024 * 1024};
if (!IsWindows()) setrlimit(RLIMIT_STACK, &rl);
// set up the signal handler and alternative stack
struct sigaction sa;
struct sigaltstack ss;
ss.ss_flags = 0;
ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 8192;
ss.ss_sp = _mapanon(ss.ss_size);
ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
sa.sa_flags = SA_SIGINFO | SA_ONSTACK; // <-- important
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = CrashHandler;
sigaction(SIGBUS, &sa, 0);
sigaction(SIGSEGV, &sa, 0);
}
int StackOverflow(int f(), int n) {
if (n < INT_MAX) {
return f(f, n + 1) - 1;
} else {
return INT_MAX;
}
}
int (*pStackOverflow)(int (*)(), int) = StackOverflow;
TEST(stackoverflow, standardStack_altStack_process_longjmp) {
int jumpcode;
if (!(jumpcode = setjmp(recover))) {
exit(pStackOverflow(pStackOverflow, 0));
}
ASSERT_EQ(123, jumpcode);
ASSERT_TRUE(smashed_stack);
// here's where longjmp() gets us into trouble
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
if (IsXnu() || IsNetbsd()) {
ASSERT_EQ(SS_ONSTACK, ss.ss_flags); // wut
} else {
ASSERT_EQ(0, ss.ss_flags);
}
}

105
test/libc/thread/stackoverflow2_test.c Normal file
View file

@ -0,0 +1,105 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/sigaltstack.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/dce.h"
#include "libc/intrin/kprintf.h"
#include "libc/limits.h"
#include "libc/mem/gc.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/sysconf.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/ss.h"
#include "libc/testlib/testlib.h"
#include "libc/thread/thread.h"
/**
* stack overflow recovery technique #2
* longjmp out of signal back into thread
* simple but it can upset kernels / libraries
*/
jmp_buf recover;
volatile bool smashed_stack;
void CrashHandler(int sig, siginfo_t *si, void *ctx) {
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
smashed_stack = true;
ASSERT_TRUE(__is_stack_overflow(si, ctx));
longjmp(recover, 123);
}
int StackOverflow(int f(), int n) {
if (n < INT_MAX) {
return f(f, n + 1) - 1;
} else {
return INT_MAX;
}
}
int (*pStackOverflow)(int (*)(), int) = StackOverflow;
void *MyPosixThread(void *arg) {
int jumpcode;
struct sigaction sa, o1, o2;
struct sigaltstack ss;
ss.ss_flags = 0;
ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 4096;
ss.ss_sp = gc(malloc(ss.ss_size));
ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
sa.sa_flags = SA_SIGINFO | SA_ONSTACK; // <-- important
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = CrashHandler;
sigaction(SIGBUS, &sa, &o1);
sigaction(SIGSEGV, &sa, &o2);
if (!(jumpcode = setjmp(recover))) {
exit(pStackOverflow(pStackOverflow, 0));
}
ASSERT_EQ(123, jumpcode);
sigaction(SIGSEGV, &o2, 0);
sigaction(SIGBUS, &o1, 0);
// here's where longjmp() gets us into trouble
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
if (IsXnu() || IsNetbsd()) {
ASSERT_EQ(SS_ONSTACK, ss.ss_flags); // wut
} else {
ASSERT_EQ(0, ss.ss_flags);
}
return 0;
}
TEST(stackoverflow, standardStack_altStack_thread_longjmp) {
pthread_t th;
struct sigaltstack ss;
for (int i = 0; i < 2; ++i) {
smashed_stack = false;
pthread_create(&th, 0, MyPosixThread, 0);
pthread_join(th, 0);
ASSERT_TRUE(smashed_stack);
// this should be SS_DISABLE but ShowCrashReports() creates an alt stack
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(0, ss.ss_flags);
}
}

116
test/libc/thread/stackoverflow3_test.c Normal file
View file

@ -0,0 +1,116 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/sigaltstack.h"
#include "libc/calls/struct/siginfo.h"
#include "libc/calls/struct/ucontext.internal.h"
#include "libc/calls/ucontext.h"
#include "libc/intrin/kprintf.h"
#include "libc/limits.h"
#include "libc/mem/gc.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/sysconf.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/ss.h"
#include "libc/testlib/testlib.h"
#include "libc/thread/thread.h"
/**
* stack overflow recovery technique #3
* rewrite thread cpu state to call pthread_exit
* this method returns gracefully from signal handlers
* unfortunately it relies on cpu architecture knowledge
*/
volatile bool smashed_stack;
void Exiter(void *rc) {
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(0, ss.ss_flags);
pthread_exit(rc);
}
void CrashHandler(int sig, siginfo_t *si, void *arg) {
ucontext_t *ctx = arg;
struct sigaltstack ss;
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(SS_ONSTACK, ss.ss_flags);
kprintf("kprintf avoids overflowing %G %p\n", si->si_signo, si->si_addr);
smashed_stack = true;
ASSERT_TRUE(__is_stack_overflow(si, ctx));
//
// the backtrace will look like this
//
// 0x000000000042561d: pthread_exit at pthread_exit.c:99
// 0x0000000000418777: Exiter at stackoverflow2_test.c:40
// 0x00000000004186d8: CrashHandler at stackoverflow2_test.c:49
// 0x000000000041872a: StackOverflow at stackoverflow2_test.c:53
// 0x000000000041872a: StackOverflow at stackoverflow2_test.c:53
// 0x000000000041872a: StackOverflow at stackoverflow2_test.c:53
// ...
//
ctx->uc_mcontext.ARG0 = 123;
ctx->uc_mcontext.PC = (long)Exiter;
ctx->uc_mcontext.SP += 32768;
ctx->uc_mcontext.SP &= -16;
ctx->uc_mcontext.SP -= 8;
}
int StackOverflow(int f(), int n) {
if (n < INT_MAX) {
return f(f, n + 1) - 1;
} else {
return INT_MAX;
}
}
int (*pStackOverflow)(int (*)(), int) = StackOverflow;
void *MyPosixThread(void *arg) {
struct sigaction sa;
struct sigaltstack ss;
ss.ss_flags = 0;
ss.ss_size = sysconf(_SC_MINSIGSTKSZ) + 4096;
ss.ss_sp = gc(malloc(ss.ss_size));
ASSERT_SYS(0, 0, sigaltstack(&ss, 0));
sa.sa_flags = SA_SIGINFO | SA_ONSTACK; // <-- important
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = CrashHandler;
sigaction(SIGBUS, &sa, 0);
sigaction(SIGSEGV, &sa, 0);
exit(pStackOverflow(pStackOverflow, 0));
return 0;
}
TEST(stackoverflow, standardStack_altStack_thread_teleport) {
void *res;
pthread_t th;
struct sigaltstack ss;
smashed_stack = false;
pthread_create(&th, 0, MyPosixThread, 0);
pthread_join(th, &res);
ASSERT_EQ((void *)123L, res);
ASSERT_TRUE(smashed_stack);
// this should be SS_DISABLE but ShowCrashReports() creates an alt stack
ASSERT_SYS(0, 0, sigaltstack(0, &ss));
ASSERT_EQ(0, ss.ss_flags);
}

2
third_party/make/job.c vendored
View file

@ -1939,7 +1939,7 @@ child_execute_job (struct childbase *child,
(STRING_SIZE_TUPLE (".PLEDGE"),
c ? c->file : 0, 0));
promises = ps ? xstrdup (ps) : 0;
if (ParsePromises (promises, &ipromises))
if (ParsePromises (promises, &ipromises, 0))
{
OSS (error, NILF, "%s: invalid .PLEDGE string: %s",
argv[0], strerror (errno));

2
tool/build/pledge.c
View file

@ -785,7 +785,7 @@ int main(int argc, char *argv[]) {
}
}
if (ParsePromises(g_promises, &ipromises) == -1) {
if (ParsePromises(g_promises, &ipromises, 0) == -1) {
kprintf("error: bad promises list: %s\n", g_promises);
_Exit(21);
}